Hybrid vehicles that have dual electric/combustion drive systems present challenges relating to packaging the components of both systems in the space available in the vehicle structure. Electric drive systems require substantial space for batteries and electric motor components. Combustion systems require substantial space for the engine and fuel tank. Batteries and fuel tanks are generally located in interior locations spaced from the perimeter of the vehicle to satisfy test requirements. Availability of protective interior locations for batteries and fuel tanks is limited.
One proposed solution to providing space for the batteries of a hybrid vehicle is to locate the battery in front of the rear sub-frame. To accommodate this battery location, the fuel tank is moved from a location in front of a crossbar of a rear sub-frame that includes a front and rear cross member connected by longitudinal side bars and is placed between the rear wheels and rear suspension components. The front cross member was eliminated to enable the fuel tank to be moved to a more rearward location between the rear wheels. Elimination of the front cross member resulted in excessive deformation in the sub-frame and fuel tank strain in the 50 MPH 70% offset Moving Deformable Barrier (MDB) rear impact test.
One possible solution to the problem of excessive deformation was to increase the thickness of the walls of the longitudinal side bars but this was unacceptable because it would result in a considerable increase in the weight of the vehicle. Another proposed solution was to locally reinforce the longitudinal side bars with patches of metal made of the same material as the longitudinal side bars in localized areas to avoid excessive added weight but his approach failed to eliminate the excessive deformation of the longitudinal side bars. Reinforcing an internal radius of a bend resulted in excessive splitting of a corresponding external radius. Reinforcing the external radius resulted in excessive bending of the corresponding internal radius.
This disclosure is directed to providing a solution to the above problems and other problems as summarized below.